To make the crumpets, sieve the flour, add the sugar into a bowl. Dissolve the yeast in 270ml/9fl½ oz warm water. Make a well in the centre of the flour and add the yeast mixture. Gradually incorporate the flour into the centre and beat until you have a smooth batter. Allow to rest for 1 hour.
Add the bicarbonate of soda to the batter and mix in a further 90ml/3fl oz water.
Put the rings on a griddle pan placed over a medium heat. Fill three-quarters with the batter. Cook the crumpets for 4 minutes, then remove the rings. There should be a large number of very small holes on the surface.
Turn the crumpets over and cook until light in colour. Take off the griddle and allow to cool.
Heat a little duck fat in a frying pan and fry the panko breadcrumbs until golden. Drain on kitchen paper and season with salt.
Heat the butter in a frying pan and fry the shiitake. Add the soy, Tabasco sauce, mirin, rice wine vinegar and stock.
Heat a little duck fat in a frying pan and fry the duck hearts for 2–3 minutes, or until cooked through. Deglaze the pan with the sherry vinegar then add the yeast extract demi-glace. Allow to bubble until you have a smooth sauce.
Divide the crumpets between four plates. Top with a duck hearts and shiitake mushrooms and pour over the duck sauce. Top with slices of smoked duck breast, shavings of goats’ cheese and the lettuce leaves. Sprinkle with the breadcrumbs and serve.